1. Field of the Invention
The present invention relates to a piezoelectric inkjet printer head.
2. Description of Related Art
Typical examples of MEMS (Micro-Electro-Mechanical System) devices are inkjet printer heads, which are broadly classified into a piezoelectric type (piezo type) and a thermal type (bubble type) by ink ejecting mechanism.
The piezoelectric inkjet printer head includes a silicon substrate having a pressure chamber and a diaphragm formed by micro-processing the silicon substrate. The diaphragm faces the pressure chamber from one side of the pressure chamber. A piezoelectric element is disposed on a side of the diaphragm opposite from the pressure chamber. A plate is bonded to the silicon substrate so as to close the pressure chamber from a side of the pressure chamber opposite from the diaphragm. The plate has a nozzle (ejection port) communicating with the pressure chamber. When a voltage is applied to the piezoelectric element, the diaphragm is deformed together with the piezoelectric element. The deformation of the diaphragm pressurizes an ink contained in the pressure chamber, whereby the ink is ejected from the nozzle.
In the thermal inkjet printer head, on the other hand, a heater is provided in an ink flow passage for heating ink. When the ink is heated by the heater in the ink flow passage, bubbles occurring in the ink are expanded to force out the ink from a nozzle communicating with the ink flow passage.